Ukraine's acting president has said that Ukraine's army is on "full combat alert," as pro-Russian separatists seized the administrative headquarters in another eastern town.
Oleksandr Turchynov told a meeting of regional governors in Kyiv that "the threat of Russia starting a war against mainland Ukraine is real."
However, Turchynov was critical of the country's "helpless" security forces, saying they were "unable to carry out their duties of protecting citizens."
Furthermore, Turchynov added that some of them "are either helping or cooperating with terrorist organizations."
His statement came as Ukraine's army and police appeared to be making little progress in a high-profile operation to try to prevent pro-Russian separatists from expanding their grip over towns in the east of the country.
Turchynov several weeks ago also announced Ukraine's defense forces had been put on high alert.
But that appeared to do little to prevent separatists from occupying government buildings and police headquarters in about a dozen eastern towns and cities in recent weeks.
In the latest incident, pro-Russian activists on April 30 seized a government building and the police headquarters in the town of Horlivka.
On April 29, pro-Russian demonstrators overran and seized the regional administration building in the eastern city of Luhansk, prompting Turchynov to abruptly dismiss the local police commanders for what he called "inaction, powerlessness, and in some cases criminal treachery."
War Of Words
Meanwhile, the United States and Russia have been blaming each other for provoking unrest in Ukraine.
U.S. Secretary of State John Kerry on April 29 accused Moscow of accelerating the crisis in Ukraine instead of sticking to an agreement to ratchet back tensions
The same day, Russian President Vladimir Putin said the West stirred up trouble in Ukraine and was now seeking a scapegoat. He said that was why it is introducing sanctions against Russia.
He also said there was no Russian military in Ukraine.
German Chancellor Angela Merkel on April 29 called again on Moscow to refrain from meddling in Ukraine's affairs, saying that "Russia has no right to interfere" in the decisions made by the Ukrainian authorities.
Merkel added that "if Russia does not stick to the rules of international law, then we must respond with sanctions, as we have already done so."
Merkel spoke after the European Union released the names of 15 individuals who are being targeted by fresh sanctions due to their roles in the Ukraine crisis.
The new sanctions list includes General Valery Gerasimov, chief of the Russian General Staff, and Lieutenant General Igor Sergun, who was identified as head of the Russian military intelligence agency (GRU).
With reporting by Reuters, AFP, and UNIAN